Abstract

Introduction

The clinical and economic consequences of the emergence of multidrug-resistant Gram-negative
bacteria in the intensive care unit (ICU) setting, combined with the high mortality
rate among patients with nosocomial pneumonia, have stimulated a search for alternative
therapeutic options to treat such infections. The use of adjunctive therapy with aerosolized
colistin represents one of these. There is extensive experience with use of aerosolized
colistin by patients with cystic fibrosis, but there is a lack of data regarding the
use of aerosolized colistin in patients without cystic fibrosis.

Methods

We conducted the present study to assess the safety and effectiveness of aerosolized
colistin as an adjunct to intravenous antimicrobial therapy for treatment of Gram-negative
nosocomial pneumonia. We retrospectively reviewed the medical records of patients
hospitalized in a 450-bed tertiary care hospital during the period from October 2000
to January 2004, and who received aerosolized colistin as adjunctive therapy for multidrug-resistant
pneumonia.

Results

Eight patients received aerosolized colistin. All patients had been admitted to the
ICU, with mean Acute Physiological and Chronic Health Evaluation II scores on the
day of ICU admission and on day 1 of aerosolized colistin administration of 14.6 and
17.1, respectively. Six of the eight patients had ventilator-associated pneumonia.
The responsible pathogens were Acinetobacter baumannii (in seven out of eight cases) and Pseudomonas aeruginosa (in one out of eight cases) strains. Half of the isolated pathogens were sensitive
only to colistin. The daily dose of aerosolized colistin ranged from 1.5 to 6 million
IU (divided into three or four doses), and the mean duration of administration was
10.5 days. Seven out of eight patients received concomitant intravenous treatment
with colistin or other antimicrobial agents. The pneumonia was observed to respond
to treatment in seven out of eight patients (four were cured and three improved [they
were transferred to another facility]). One patient deteriorated and died from septic
shock and multiple organ failure. Aerosolized colistin was well tolerated by all patients;
no bronchoconstriction or chest tightness was reported.

Conclusion

Aerosolized colistin may be a beneficial adjunctive treatment in the management of
nosocomial pneumonia (ventilator associated or not) due to multidrug-resistant Gram-negative
bacteria.